/*
 * Copyright (C) 2012 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.facebook.zookeeper.election;

public interface LeaderElectionCallback {
  /**
   * Callback signaling that the current host has won the election.
   */
  public void elected();

  /**
   * Callback signaling that the current host was unexpectedly removed from
   * the election or from leadership (e.g. session expiration).
   * Note: Calls to withdraw and cycle will NOT generate removed signals.
   */
  public void removed();

  /**
   * Callback signaling an asynchronous error.
   * @param exception
   */
  public void error(Exception exception);
}
